post admin ajax slows down website

hi,
post admin ajax taking time to load and slows down the entire website. Disabled the plugin and confirmed this issue is by WOCS plugin only.
https://gtmetrix.com/reports/alseller.com/K1H5zQar
tried by enabling and disabling i am using cache plugin on my site option but no use.
please help.
am using country based checkout currency-code, in function file. (find the code from your FAQ page).

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